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1.
New Ternary Germanides: The Compounds Ln 4Zn5Ge6 ( Ln : Gd, Tm, Lu) Three new ternary germanides were prepared by heating mixtures of the elements. Gd4Zn5Ge6 (a = 4.249(3), b = 18.663(17), c = 15.423(6) Å), Tm4Zn5Ge6 (a = 4.190(1), b = 18.410(5), c = 15.105(5) Å), and Lu4Zn5Ge6 (a = 4.179(1), b = 18.368(4), c = 15.050(3) Å) are isotypic and crystallize in a new structure type (Cmc21; Z = 4), composed of edge‐ and corner‐sharing ZnGe4 tetrahedra. The rare‐earth atoms fill channels of the Zn,Ge network running along the a axis and predominantly have an octahedral coordination of Ge atoms or a pentagonal prismatic environment of Zn and Ge atoms. The ZnGe4 tetrahedra are orientated to each other so that two of six Ge atoms form pairs, while the other ones have no homonuclear contacts. This is in accord with an ionic splitting of the formula: (Ln3+)4(Zn2+)5(Ge3–)2(Ge4–)4. LMTO band structure calculations support the interpretation of bondings derived from interatomic distances. The metallic conductivity of these compounds expected from the electronic band structure was confirmed by measurements of the electrical resistance of Tm4Zn5Ge6.  相似文献   

2.
Transparent platelet‐shaped green single crystals of the title compound were obtained by the reaction of cesium bromide, praseodymium, sulfur, and red phosphorus in the molar ratio 1:2:8:2 with an excess of CsBr as flux in evacuated silica ampoules at 950 °C for fourteen days. Cs3Pr5[PS4]6 crystallizes monoclinically in the space group C2/c (a = 1627.78(7), b = 1315.09(6), c = 2110.45(9) pm, β = 103.276(5)°; Z = 4). Its crystal structure is different from all the other alkali‐metal containing ortho‐thiophosphates of the lanthanides, since it is not possible to formulate a layer containing the praseodymium centered sulfur polyhedra ([PrS8]13—, d(Pr—S) = 286 — 307 pm) and the isolated [PS4]3— tetrahedra (d(P—S) = 202 — 207 pm, ?(S—P—S) = 104 — 106°). All these tetrahedra are edge‐sharing with the metal polyhedra to build up a framework instead. The coordination sphere of the half occupied (Cs2)+ cations (CN = 10 + 2) can be described as two six‐membered sulfur rings in chair conformation containing a “cesium‐pair” in the middle. In contrast the (Cs1)+ cations are surrounded in the not unusual configuration of tetracapped trigonal prisms (CN = 10, better 10 + 2 as well).  相似文献   

3.
Motifs of Closest Packings: The Compounds Zn3(PS4)2 and LiZnPS4 The crystal structure of Zn3(PS4)2 was determined by single crystal X‐ray methods. The compound crystallizes tetragonally (Pn2; a = 7.823(1), c = 9.053(1)Å; Z = 2) with a new structure type built up by corner‐sharing ZnS4 tetrahedra, which form two‐dimensional layers. Between them the P atoms are coordinated likewise tetrahedrally by sulfur. The PS4 tetrahedra are arranged according to the motif of the cubic closest packing with zinc in three quarters of the tetrahedral voids. LiZnPS4 (I4¯; a = 5.738(1), c = 8.914(1)Å; Z = 2) was synthesized by heating the elements at 400 °C. In comparison with Zn3(PS4)2 one Zn atom is replaced by two Li atoms. The metal atoms are located in the centres of the sulfur tetrahedra in such a way that the unit cell volume is only about half that of the zinc compound. In this packing of the PS4 units all the tetrahedral voids are occupied by lithium and zinc atoms. Chemical bonding in LiZnPS4 is discussed by means of the electron localization function ELF.  相似文献   

4.
New Germanides with an Ordered Variant of the Ce3Pt4Ge6 Type of Structure – The Compounds Ln3Pt4Ge6 (Ln: Pr–Dy) Six new germanides Ln3Pt4Ge6 with Ln = Pr–Dy were synthesized by heating mixtures of the elements at 900 °C, annealing the inhomogeneous powders at 1050‐1100 °C for six days and then cooling down from 700 °C in the course of two months. The crystal structures of Pr3Pt4Ge6 (a = 26.131(5), b = 4.399(1), c = 8.820(2) Å), Sm3Pt4Ge6 (a = 25.974(3), b = 4.356(1), c = 8.748(1) Å), and Dy3Pt4Ge6 (a = 26.079(5), b = 4.311(1), c = 8.729(2) Å) were determined by single crystal X‐ray methods. The compounds are isotypic (Pnma, Z = 4) and crystallize with an ordered variant of the Ce3Pt4Ge6 type of structure (Cmcm, Z = 2) consisting of CaBe2Ge2‐ and YIrGe2‐analogous units. The platinum atoms are located in distorted square pyramids of germanium atoms and build up with them a three‐dimensional network. The coordination polyhedra of the platinum and germanium atoms around the rare‐earth metal atoms are pentagonal and hexagonal prisms. These are completed by some additional atoms resulting in coordination numbers of 14 and 15 respectively. The other germanides were investigated by powder methods resulting in the following lattice constants: a = 26.067(6), b = 4.388(1), c = 8.800(2) Å for Ln = Nd; a = 25.955(7), b = 4.337(1), c = 8.728(2) Å for Ln = Gd; a = 25.944(5), b = 4.322(1), c = 8.698(2) Å for Ln = Tb. The atomic arrangement of Ln3Pt4Ge6 is compared with the well‐known monoclinic structure of Y3Pt4Ge6.  相似文献   

5.
Synthesis and Crystal Structures of Ln 2Al3Si2 and Ln 2AlSi2 ( Ln : Y, Tb–Lu) Eight new ternary aluminium silicides were prepared by heating mixtures of the elements and investigated by means of single‐crystal X‐ray methods. Tb2Al3Si2 (a = 10.197(2), b = 4.045(1), c = 6.614(2) Å, β = 101.11(2)°) and Dy2Al3Si2 (a = 10.144(6), b = 4.028(3), c = 6.580(6) Å, β = 101.04(6)°) crystallize in the Y2Al3Si2 type structure, which contains wavy layers of Al and Si atoms linked together by additional Al atoms and linear Si–Al–Si bonds. Through this there are channels along [010], which are filled by Tb and Dy atoms respectively. The silicides Ln2AlSi2 with Ln = Y (a = 8.663(2), b = 5.748(1), c = 4.050(1) Å), Ho (a = 8.578(2), b = 5.732(1), c = 4.022(1) Å), Er (a = 8.529(2), b = 5.719(2), c = 4.011(1) Å), Tm (a = 8.454(5), b = 5.737(2), c = 3.984(2) Å) and Lu (a = 8.416(2), b = 5.662(2), c = 4.001(1) Å) crystallize in the W2CoB2 type structure (Immm; Z = 2), whereas the structure of Yb2AlSi2 (a = 6.765(2), c = 4.226(1) Å; P4/mbm; Z = 2) corresponds to a ternary variant of the U3Si2 type structure. In all compounds the Si atoms are coordinated by trigonal prisms of metal atoms, which are connected by common faces so that Si2 pairs (dSi–Si: 2.37–2.42 Å) are formed.  相似文献   

6.
Five new compounds of the BaNiNd2O5-type with the rare earth elements Sm, Gd, Ho, Er, Tm are prepared and examined by X-ray single crystal technique. The atomic parameters are refined by least-square methods. The crystal chemical differences in the surrounding of rare earth ions in BaMLn 2O5-compounds (M=Pt, Pd, Cu, Ni) are discussed.
  相似文献   

7.
Three Alkali‐Metal Erbium Thiophosphates: From the Layered Structure of KEr[P2S7] to the Three‐Dimensional Cross‐Linkage in NaEr[P2S6] and Cs3Er5[PS4]6 The three alkali‐metal erbium thiophosphates NaEr[P2S6], KEr[P2S7], and Cs3Er5[PS4] show a small selection of the broad variety of thiophosphate units: from ortho‐thiophosphate [PS4]3? and pyro‐thiophosphate [S3P–S–PS3]4? with phosphorus in the oxidation state +V to the [S3P–PS3]3? anion with a phosphorus‐phosphorus bond (d(P–P) = 221 pm) and tetravalent phosphorus. In spite of all differences, a whole string of structural communities can be shown, in particular for coordination and three‐dimensional linkage as well as for the phosphorus‐sulfur distances (d(P–S) = 200 – 213 pm). So all three compounds exhibit eightfold coordinated Er3+ cations and comparably high‐coordinated alkali‐metal cations (CN(Na+) = 8, CN(K+) = 9+1, and CN(Cs+) ≈ 10). NaEr[P2S6] crystallizes triclinically ( ; a = 685.72(5), b = 707.86(5), c = 910.98(7) pm, α = 87.423(4), β = 87.635(4), γ = 88.157(4)°; Z = 2) in the shape of rods, as well as monoclinic KEr[P2S7] (P21/c; a = 950.48(7), b = 1223.06(9), c = 894.21(6) pm, β = 90.132(4)°; Z = 4). The crystal structure of Cs3Er5[PS4] can also be described monoclinically (C2/c; a = 1597.74(11), b = 1295.03(9), c = 2065.26(15) pm, β = 103.278(4)°; Z = 4), but it emerges as irregular bricks. All crystals show the common pale pink colour typical for transparent erbium(III) compounds.  相似文献   

8.
The metal thiophosphates Rb2AgPS4 ( 2 ), RbAg5(PS4)2 ( 3 ), and Rb3Ag9(PS4)4 ( 4 ) were synthesized by stoichiometric reactions, whereas Rb6(PS5)(P2S10) ( 1 ) was prepared with excess amount of sulfur. The compounds crystallize as follows: 1 monoclinic, P21/c (no. 14), a = 17.0123(7) Å, b = 6.9102(2) Å, c = 23.179(1) Å, β = 94.399(4)°; 2 triclinic, P$\bar{1}$ (no. 2), a = 6.600(1) Å, b = 6.856(1) Å, c = 10.943(3) Å, α = 95.150(2)°, β = 107.338(2)°, γ = 111.383(2)°; 3 orthorhombic, Pbca (no. 61), a = 12.607(1) Å, b = 12.612(1) Å, c = 17.759(2) Å; 4 orthorhombic, Pbcm (no. 57), a = 6.3481(2) Å, b = 12.5782(4) Å, c = 35.975(1) Å. The crystal structures contain discrete units, chains, and 3D polyanionic frameworks composed of PS4 tetrahedral units arranged and connected in different manner. Compounds 1 – 3 melt congruently, whereas incongruent melting behavior was observed for compound 4 . 1 – 4 are semiconductors with bandgaps between 2.3 and 2.6 eV and thermally stable up to 450 °C in an inert atmosphere.  相似文献   

9.
Ternary Lithium Rare Earth Nitrates with Lonesome Nitrate Ions: Li3[M(NO3)5](NO3) (M = Gd? Lu, Y). The Crystal Structure of Li3Er(NO3)6 Single crystals of the ternary nitrate Li3Er(NO3)6 are obtained from a solution of “Er(NO3)3” in the melt of LiNO3. In Li3Er(NO3)6 (monoclinic, P21/n, Z = 4; a = 776.0(1); b = 748.86(8); c = 2 396(1) pm; β = 90.76(3)°; R1 = 0.0490; wR2 = 0.0792), Er3+ is surrounded by five bidentate nitrate ligands yielding the anionic units [Er(NO3)5]2?. These are arranged in the direction of the 21 screw axis. Two lonesome NO3? ions are in the middle of such a “helix” and are connected by Li+ with the anions [Er(NO3)5]2?. The helices are moved against each other by about half of the lattice constant a and are connected by further Li+ ions.  相似文献   

10.
The Crystal Structures of the Lithium Hydroxide Halides Li4(OH)3Br and Li4(OH)3I Using single crystal analysis and powder diffraction data the crystal structures of the lithium hydroxide halides Li4(OH)3Br and Li4(OH)3I were solved and refined. Li4(OH)3Br crystallises in the space group P21/m and is isotypic with the lighter homologue Li4(OH)3Cl. (Rietveld‐refinement; T = 293 K; a = 545, 41(1); b = 758, 13(1); c = 650, 20(1) pm; β = 93, 82(1)°; Z = 2; 300 unique reflections; Rp = 0, 106; Rwp = 0, 109; Rexp = 0, 081). Li4(OH)3I crystallises in the space group Pmmn in a variant of the LiOH structure in which 1/4 of the hydroxide anions are replaced by iodide anions. (Single crystal analysis; T = 100 K; a = 1029, 5(4); b = 525, 9(2); c = 573, 2(2) pm; Z = 2; 392 unique reflections; R1 = 0, 0642).  相似文献   

11.
Syntheses and Crystal Structures of New Alkali Metal Rare‐Earth Tellurides of the Compositions KLnTe2 (Ln = La, Pr, Nd, Gd), RbLnTe2 (Ln = Ce, Nd) and CsLnTe2 (Ln = Nd) Of the compounds ALnQ2 (A = Na, K, Rb, Cs; Ln = rare earth‐metal; Q = S, Se, Te) the crystal structures of the new tellurides KLaTe2, KPrTe2, KNdTe2, KGdTe2, RbCeTe2, RbNdTe2, and CsNdTe2 were determined by single‐crystal X‐ray analyses. They all crystallize in the α‐NaFeO2 type with space group R3¯m and three formula units in the unit cell. The lattice parameters are: KLaTe2: a = 466.63(3) pm, c = 2441.1(3) pm; KPrTe2: a = 459.73(2) pm, c = 2439.8(1) pm; KNdTe2: a = 457.83(3) pm, c = 2443.9(2) pm; KGdTe2: a = 449.71(2) pm, c = 2443.3(1) pm; RbCeTe2: a = 465.18(2) pm, c = 2533.6(2) pm; RbNdTe2: a = 459.80(3) pm, c = 2536.5(2) pm, and CsNdTe2: a = 461.42(3) pm, c = 2553.9(3) pm. Characteristics of the α‐NaFeO2 structure type as an ordered substitutional variant of the rock‐salt (NaCl) type are layers of corner‐sharing [(A+/Ln3+)(Te2—)6] octahedra with a layerwise alternating occupation by the cations A+ and Ln3+.  相似文献   

12.
Anhydrous Sulfates of Rare Earth Elements: Syntheses and Crystal Structures of Y2(SO4)3 and Sc2(SO4)3 The reaction of YCl3 and Li2SO4 in sealed gold ampoules yields colorless single crystals of Y2(SO4)3. According to the X‐ray single crystal determination the compound crystallizes with orthorhombic symmetry (Pbcn, Z = 4, a = 1273.97(13), b = 916.76(9), c = 926.08(7) pm, Rall = 0.0274). The crystal structure is buildt up from [YO6] octahedra and sulfate tetrahedra connected via all vertices. In the same way [ScO6] octahedra and sulfate groups are connected in the crystal structure of Sc2(SO4)3 (trigonal, R‐3, Z = 6, a = 870.7(1), c = 2247.0(4) pm, Rall = 0.0255). Single crystals of Sc2(SO4)3 were obtained via crystallisation of powder samples from a NaCl melt. The crystal structures of both compounds are closely related to each other and to the binary sulfides Rh2S3 and Lu2S3; the structures are the same with the complex SO42– ions replacing the S2– ions of the sulfides.  相似文献   

13.
对四方磷钇矿型结构的LnPS4系列化合物Raman光谱的研究表明,PS3-4阴离子的对称伸缩振动频率ν1随镧系收缩呈线性有规则增大,非四方晶系LuPS4的ν1值明显偏离该直线,这种变化趋势与相应结构的变化一致。  相似文献   

14.
A new chromium thiophosphate, K3Cr2(PS4)3 has been prepared and characterized by single‐crystal diffraction, temperature dependent magnetic susceptibility measurements and optical spectroscopy. K3Cr2(PS4)3 crystallizes in the monoclinic space group P21/n (No. 14) with a = 9.731(2) Å, b = 11.986(2) Å, c = 17.727(4) Å, β = 96.52(2)°, V = 2054.2(2) Å3, Z = 4, and R = 0.044. The anionic part of the structure consists of dimeric Cr23‐S3PS)2 units which are linked by bidentate PS4 groups to form infinite one‐dimensional [S2PS2Cr23S3PS)2]3— chains separated by K+ cations. The CrIII centers of the Cr23‐S3PS)2 units are antiferromagnetically coupled. The magnetic susceptibility data may be fitted using a D‐Heisenberg model for S = 3/2 with g = 2.02 and J/k = 10K. K3Cr2(PS4)3 is semiconducting with an optical band gap of 1.35 eV.  相似文献   

15.
The Compound La5Br4Al4 and the Topological Relation with the Ln3ClGa4 Structure Type The compound La5Br4Al4 can be prepared from La metal, LaBr3 and Al filings at 950 °C with a yield of 20 %. It crystallizes tetragonally in I4/mcm with a = b = 8.292(1)Å, c = 20.122(4)Å. In the crystal structure 3 sheets of Br/La, La/Al, and La/Br atoms, respectively, are stacked along [001] and are connected by single layers of Br atoms. The Al atoms form undulated nets of condensed Al8 and Al4 rings. The La atoms are arranged in tetragonal antiprisms, centered by the second kind of crystallographically different La atoms. These units are connected to sheets. In La3ClGa4 the identical 3 sheets formed by La, Ga, Cl atoms are present, however, not separated by the additional layers of Br atoms as in La5Br4Al4.  相似文献   

16.
New ternary phosphides Ln25Ni49P33 (Ln = Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er) have been synthesized by arc melting of pure components. Crystal structure has been determined for Sm25Ni49P33 using X‐ray powder diffraction data and the Rietvelt method: P6m2, a = 22.096(4), c = 3.8734(9) Å, R = 0.096. Crystal structure of Sm25Ni49P33 is of a new type and belongs to large family of ternary compounds with trigonal‐prismatic coordination of the smallest size atoms and metal to nonmetal ratio equal or close to 2 : 1. It is a member of homologous subseries of the compounds with unit cell contents described by general chemical formula R M X . Lattice parameters of the isotypic compounds Ln25Ni49P33 have been refined using X‐ray powder diffraction data.  相似文献   

17.
Ternary Halides of the A3MX6Type. VII. The Bromides Li3MBr6 (M=Sm? Lu, Y): Synthesis, Crystal Structure, and Ionic Mobility The bromides Li3MBr6 (M=Sm? Lu, Y) are obtained from the binary components LiBr and MBr3. They crystallize with a substitution/addition variant of the AlCl3? type of structure as was established from single crystal X-ray diffraction data for Li3ErBr6 (monoclinic, C2/m, Z = 2, a = 689.0(3), b = 1191.6(9), c = 684.2(6) pm, β = 109.77(6)°) and by powder X-ray diffraction for the remaining bromides. They are isotypic with Na3GdI6 and Li3ScCl6, respectively. Impedance spectroscopy and 7Li-NMR spectroscopy show that the lithium ions are highly mobile.  相似文献   

18.
The crystal structure of the RE2PbS4 (RE = Y, Dy, Ho, Er and Tm) compounds (space group Cmc21, Pearson symbol oC112, a = 0.79301(3) nm, b = 2.86966(9) nm, c = 1.20511(5) nm, RBragg = 0.0979 for Y2PbS4; a = 0.79484(8) nm, b = 2.8721(3) nm, c = 1.2039(1) nm, for Dy2PbS4; a = 0.79081(2) nm, b = 2.86222(7) nm, c = 1.20220(4) nm, RBragg = 0.0859 for Ho2PbS4; a = 0.7863(2) nm, b = 2.8525(5) nm, c = 1.1995(2) nm, R1 = 0.0482 for Er2PbS4 and a = 0.78419(3) nm, b = 2.84184(9) nm, c = 1.19655(4) nm, RBragg = 0.0893 for Tm2PbS4) was investigated by means of X‐ray single crystal and powder diffraction. Each RE atoms is octahedrally coordinated by six S atoms. Each Pb atoms is surrounded by seven S atoms to form a mono‐capped trigonal prism.  相似文献   

19.
Ruby‐red, bead‐shaped single crystals of C‐type La2Se3 (a = 905.21(6) pm), Pr2Se3 (a = 891.17(6) pm), and Gd2Se3 (a = 872.56(5) pm) are obtained by oxidation of the respective rare‐earth metal (M = La, Pr and Gd) with selenium (molar ratio 2 : 3) in evacuated silica tubes at 750 °C in the presence of fluxing CsCl within seven days. Their crystal structure belongs to a cation‐deficient Th3P4‐type variant (cubic, I 4 3d) according to M2.6670.333Se4 (Z = 4) or M2Se3 (Z = 5.333) offering coordination numbers of eight (Se2– arranged as trigonal dodecahedra) to the M3+ cations. In spite of the high Cs+ activity in molten CsCl, no cesium incorporation into the M5.3330.667Se8‐frame structure (e. g. as CsM5Se8 with Z = 2) could be achieved, judged from both results of electron beam X‐ray microanalyses and refined occupation factors of the metal position very close to x = 8/9 for M3xSe4.  相似文献   

20.
Tetrafluoroaurates(III) of Lanthanoides M2F[AuF4]5 (M = Tb, Dy, Ho, Er) Tetrafluoroaurates(III) M2F[AuF4]5 with M = Tb, Dy, Ho, Er, all yellow, have been obtained. From single crystal data they crystallize triclinic, space group P1 -C1i (No. 2) with Tb: a = 1 194,34(7) pm, b = 798,46(6) pm, c = 902,02(7) pm, α = 89,033(7)°, β = 88,990(6)°, γ = 89,006(7)°; Dy: a = 1 191,66(9) pm, b = 796,33(8) pm, c = 899,65(9) pm, α = 88,956(8)°, β = 89,056(8)°, γ = 88,972(8)°; Ho: a = 1 189,06(10) pm, b = 795,46(6) pm, c = 896,81(7) pm, α = 88,912(8)°, β = 89,101(7)°, γ = 88,873(8)°; Er: a = 1 185,20(40), b = 793,98(14), c = 893,83(20), α = 88,751(23)°, β = 89,187(26)°, γ = 88,884(9)°  相似文献   

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